Cardiac analysis system for comparing clinical and induced ventricular tachycardia events

Abstract

A cardiac analysis system is provided that includes an implantable medical device (IMD), at least one sensor, and an external device. The IMD has electrodes positioned proximate to a heart that sense first cardiac signals of the heart and associated with a clinical ventricular tachycardia (VT) event and second cardiac signals associated with an induced VT event. The sensor measures first and second cardiac parameters of the heart associated with the clinical and induced VT events, respectively. The external device is configured to receive the first and second cardiac signals associated with the clinical and the induced VT events and the first and second cardiac parameters associated with the clinical and the induced VT events. The external device compares the first and second cardiac signals and compares the first and second cardiac parameters to determine if the clinical and induced VT events are a common type of VT event.

What is claimed is: 
     
       1. A cardiac analysis system comprising:
 an implantable medical device (IMD) including electrodes configured to be positioned proximate to a heart, the electrodes sensing cardiac signals of the heart including first cardiac signals associated with a clinical ventricular tachycardia (VT) event of the heart and second cardiac signals associated with an induced VT event of the heart; 
 at least one sensor configured to measure non-electrical cardiac parameters of the heart including first non-electrical cardiac parameters associated with the clinical VT event and second non-electrical cardiac parameters associated with the induced VT event and wherein the at least one sensor is selected from the group consisting of a blood pressure sensor, a blood oxygen sensor, a photoplethysmograph (PPG) sensor, a glucose sensor, an acoustic sensor, and a saturated venous oxygen sensor; and 
 an external device configured to receive the first and second cardiac signals, the external device configured to receive the first and second non-electrical cardiac parameters, the external device configured to present the first cardiac signals and the first non-electrical cardiac parameters with the second cardiac signals and the second non-electrical cardiac parameters to enable determination of when the clinical VT event and the induced VT event are a common type of VT event. 
 
     
     
       2. The cardiac analysis system of  claim 1 , wherein the external device is configured to receive the first non-electrical cardiac parameters and the first cardiac signals prior to the induced VT event. 
     
     
       3. The cardiac analysis system of  claim 1 , wherein the external device is configured to receive the second non-electrical cardiac parameters and the second cardiac signals in real time during the induced VT event. 
     
     
       4. The cardiac analysis system of  claim 1 , wherein the external device is configured to receive the second non-electrical cardiac parameters and the second cardiac signals during an ablation procedure applied to the heart and to determine when the clinical VT event and the induced VT event are the common type of VT event during the ablation procedure. 
     
     
       5. The cardiac analysis system of  claim 1 , wherein the IMD is configured to apply stimulus pulses to the heart during a pacing regimen while the IMD obtains the first cardiac signals and the at least one sensor measures the first non-electrical cardiac parameters, the IMD further configured to apply the pacing regimen to the heart while the IMD obtains the second cardiac signals and the at least one sensor measures the second non-electrical cardiac parameters. 
     
     
       6. The cardiac analysis system of  claim 1 , wherein the first and second non-electrical cardiac parameters measured by the at least one sensor are uncorrelated to the first and second cardiac signals sensed by the IMD. 
     
     
       7. The cardiac analysis system of  claim 1 , wherein the IMD is configured to deliver stimulus pulses to the heart according to a pacing regimen during the induced VT event, the IMD configured to apply the pacing regimen to the heart during a post-ablation VT event based on a comparison between the second cardiac signals associated with the induced VT event, and third cardiac signals obtained during the post-ablation VT event. 
     
     
       8. A method for comparing ventricular tachycardia (VT) events of a heart, the method comprising:
 sensing cardiac signals of the heart using electrodes positioned proximate to the heart, the cardiac signals including first cardiac signals associated with a clinical VT event and second cardiac signals associated with an induced VT event; 
 measuring non-electrical cardiac parameters representative of the heart using at least one sensor, the non-electrical cardiac parameters including first non-electrical cardiac parameters associated with the clinical VT event and second non-electrical cardiac parameters associated with the induced VT event and wherein the non-electrical cardiac parameters are selected from the group consisting of blood pressure, blood oxygen saturation, photoplethysmography, glucose level, acoustic level, and saturated venous oxygen; and 
 comparing the first cardiac signals with the second cardiac signals and comparing the first non-electrical cardiac parameters with the second non-electrical cardiac parameters to determine when the clinical VT event and the induced VT event are a common type of VT event. 
 
     
     
       9. The method of  claim 8 , wherein the sensing includes sensing the first cardiac signals prior to sensing the second cardiac signals and the measuring includes measuring the first non-electrical cardiac parameters event prior to measuring the second non-electrical cardiac parameters. 
     
     
       10. The method of  claim 8 , further comprising communicating the second cardiac signals and the second non-electrical cardiac parameters to an external device for presentation on a display device during the induced VT event. 
     
     
       11. The method of  claim 8 , wherein the sensing includes sensing the second cardiac signals during an ablation procedure applied to the heart, the measuring includes measuring the second non-electrical cardiac parameters during the ablation procedure, and the comparing includes comparing, during the ablation procedure, the second cardiac signals with the first cardiac signals and comparing the second non-electrical cardiac parameters with the first non-electrical cardiac parameters. 
     
     
       12. The method of  claim 8 , further comprising applying stimulus pulses to the heart according to a pacing regimen during the clinical VT event, wherein the sensing the first cardiac signals associated with the clinical VT event and the measuring the first non-electrical cardiac parameters associated with the clinical VT event occurs during the pacing regimen. 
     
     
       13. The method of  claim 8 , further comprising applying stimulus pulses to the heart according to a pacing regimen during the induced VT event, wherein the sensing the second cardiac signals associated with the induced VT event and the measuring the second non-electrical cardiac parameters associated with the induced VT event occurs during the pacing regimen. 
     
     
       14. The method of  claim 8 , wherein the measuring the first and second non-electrical cardiac parameters includes measuring the first and second cardiac parameters that are uncorrelated to the first and second cardiac signals of the heart. 
     
     
       15. The method of  claim 8 , further comprising supplying stimulus pulses to the heart according to a pacing regimen during the induced VT event and applying the pacing regimen to the heart during a post-ablation VT event based on a comparison between the second cardiac signals associated with the induced VT event and third cardiac signals sensed during the post-ablation VT event. 
     
     
       16. A tangible and non-transitory computer readable storage medium for a cardiac analysis system comprising an implantable medical device (IMD) having electrodes positioned proximate to a heart, at least one sensor, and an evaluation processor, the computer readable storage medium including instructions to direct the evaluation processor to:
 receive first cardiac signals sensed by the electrodes of the IMD and receive first non-electrical cardiac parameters measured by the at least one sensor and associated with a clinical ventricular tachycardia (VT) event, the first cardiac signals and the first non-electrical cardiac parameters representative of cardiac activity of the heart; 
 receive second cardiac signals sensed by the electrodes of the IMD and receive second non-electrical cardiac parameters measured by the at least one sensor and associated with an induced VT event; and 
 determine when the clinical VT event and the induced VT event are a common type of VT event by comparing the first cardiac signals associated with the clinical VT event with the second cardiac signals associated with the induced VT event and comparing the first non-electrical cardiac parameters associated with the clinical VT event with the second non-electrical cardiac parameters associated with the induced VT event. 
 
     
     
       17. The computer readable storage medium of  claim 16 , wherein the instructions direct the evaluation processor to receive the first non-electrical cardiac parameters associated with the clinical VT event and receive the first cardiac signals associated with the clinical VT event prior to the induced VT event and to receive the second non-electrical cardiac parameters associated with the induced VT event and the second cardiac signals associated with the induced VT event during the induced VT event. 
     
     
       18. The computer readable storage medium of  claim 16 , wherein the instructions direct the evaluation processor to determine if the clinical VT event and the induced VT event are the common type of VT event by comparing indices of the first cardiac signals associated with the clinical VT event with indices of the second cardiac signals associated with the induced VT event, the indices including at least one of a VT cycle length, a variability of VT cycle lengths, a rate of ventricular contraction, a variability of ventricular contractions, an amplitude, a waveform morphology measurement, or a frequency index.